Talking Cars: Computer controlled transmissions

I own a 2000 Infiniti I30 with 53,000 miles. For the last three months every few weeks when I try to start the engine, it does not crank over; it makes a terrible screeching sound when I turn the key.

Junior Damato

Q: I own a 2000 Infiniti I30 with 53,000 miles. For the last three months every few weeks when I try to start the engine, it does not crank over; it makes a terrible screeching sound when I turn the key. At the next turn of the key the engine cranks over and starts fine. I took the car to the shop and they could not duplicate the problem. What do you think?

A: It sounds like the starter drive teeth are not meshing properly with the teeth on the flywheel. I would suggest the replacement of the starter drive or complete starter.

Q: My girlfriend just purchased a 2000 Mitsubishi Gallant four-cylinder with 68,000 miles. When she steps down on the gas pedal to engage passing gear there is a loud hum sound that appears to be coming from the dashboard area. Is this normal?

A: The older four-cylinder Mitsubishi engines do have an above average vibration that can be transmitted through the whole car. Some vibration is normal. Get a couple of opinions from local shops on the noise you describe.

Q: I own a 1999 Ford F250 4.6 with a V/8 engine. The heater core has failed two times in three years. The cost of replacement is $700. The shop was at a loss for the reason the heater cores have failed. Do you have any ideas?

A: I have replaced many heater cores on Ford vehicles. I always check for technical service bulletins on all part replacement. Alldata.com lists T.S.B. #06-21-19, referring to heater core leakage. This deals with electrolysis, poor quality antifreeze and too much pressure flowing into the heater core. The bulletin also covers a lot of other models in the Ford and Lincoln family of vehicles.

Q: I own a 2003 Hyundai Santa Fe with only 19,000 miles. Occasionally, while I’m driving, the speedometer will stop working, as does the cruise control if engaged. I went to the dealer and they could not duplicate the problem and there were no trouble fault codes. They said the problem could be the speed sensor. Is there anything else to check before replacing the speed sensor?

A: The most common problem with intermittent electronic speedometer operation is the speed sensor. Most are located on the transmission. There are no bulletins or history on this problem. The best suggestion is to get into a repair shop or dealer at the time of the failure so the technician can connect a scan tool and road test the car and watch the scan tool at the same time.

Q: I was given a 1991 Cadillac Deville 4.9 with only 47,000 miles. When the weather is cold all the instrument lights blink off and on and I can also hear a clicking sound like relays. The Cadillac dealer replaced the computer; it did not fix the problem. Do you have any suggestions?

A: Whenever we get problems such as yours that are temperature related, we take the dash cluster out and put it in the freezer, then quickly connect it back into the car and check the operation. The next step is to remove the computer again if it is cold temperature related. If it is heat related, a blow dryer is used.

Q: I own a 2006 Honda Civic LX automatic transmission. When driving in heavy traffic, and at speeds under 10 miles per hour, if I take my foot of the gas, the transmission will downshift hard. When I go to accelerate, there is some hesitation and then the car will accelerate. What are your thoughts?

A: Today’s automatic transmissions are computer controlled. They rely on various input and computer programming. To date, there are no bulletins on your complaint. I would check with the dealer for their input and any possible updates. You can also manually place the transmission in first gear and shift into drive once out of traffic.

Q: I own a 1997 Honda del Sol with 90,000 miles. There is an actual squeak emitting from the engine. The dealer recommended I replace the timing belt related pulleys and regular belts. Is this something you would suggest?

A: This is absolutely the right service to have performed. The rubber timing belt wears as do the pulley and bearings that the timing belt has constant pressure on.

Q: I just purchased a 2007 Toyota Highlander four-cylinder. The manual recommends 5W20 weight oil. This seems very light for the hot summer weather. Can I mix in two quarts of 5W30 during the hot summer months?

A: The newer oil formulas of today cannot be compared with the oil of years gone by. Even high-performance big engines are using light viscosity engine oils. I would not recommend the mixing of oils, except in a case of top off only, and, even then, get the oil changed as soon as possible.

Q: I own a 2005 Pontiac GTO. On two different occasions, the antifreeze boiled over. The temperature gauge did not read high. I can also hear a bubbling sound coming from the engine compartment. The loss of coolant is minimal. The dealer has checked the car twice and could not find any problem. What do you think?

A: The radiator-cooling fan is electric and controlled by engine temperature via the computer. First, we do not know if the actual in-dash temperature gauge is accurate. Second, we do not know if the engine was overheating. A poor seal on the coolant over flow reservoir is the first place to look as well as hook up a scan tool and compare the actual engine temperature that the computer is seeing versus what the dash temperature gauge is registering. A check of hydrocarbons in the cooling system should also be checked.

Q: I own a 1999 Mercury Grand Marquis with 85,000 miles. The cruise control became stubborn. Then it stopped working altogether. Next, the overdrive button stopped working. I did find a blown fuse and replaced it. It worked for a minute and then stopped again. Also, there was a warning chime and a clicking sound from one of the doors. Can you help?

A: If you want to pursue the problem yourself, the first step is to go to Alldata.com and subscribe. The cost is only $25 for a year, and you can get any information you need to repair any problem. You will need to look at a wiring diagram and all components in the circuits involved.

Q: I own a 1997 Dodge Dakota pick up 3.9 V/6. During the first 10 to 15 minutes of driving there is some hesitation for a minute or so. I went to the shop and they checked and found a #3 and #5 misfire code stored. I had a complete tune-up, #5 cylinder new fuel injector and crankshaft sensor replacement. The hesitation is still present. The shop cannot find the source of the problem. What do you recommend?

A: The first step is to leave the truck at the shop overnight. They will hook up a scan tool and fuel pressure tester along with a spark tester, then road test the truck when cold. You may have to leave the truck for a few days so they can troubleshoot the truck. I looked your truck up on our Identifix Web site and found a history of faulty oxygen sensor problems that refer to hesitation during warm-up. I also have seen a fair share of faulty intake manifold gaskets. These problems will cause hesitation, sometimes without setting the check engine light on.

Junior Damato writes weekly about cars. You can send questions to him care of the Old Colony Memorial, 182 Standish Ave., Plymouth, MA 02360. He can be heard live on WXBR radio 1460, 7-10 a.m. Saturday mornings.

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